This invention relates to an artificial kidney system and particularly to such a system wherein patient fluid exchange can be regulated.
A conventional artificial kidney machine includes a dialyzer receiving a dialysate solution, comprising a mixture of dialysate concentrate and water, into which impurities in the patient's blood pass as the dialysate solution flows through the dialyzer. A negative pressure may be applied at the outlet of the dialyzer for withdrawing the used dialysate solution with impurities, collectively known as diffusate. Such negative pressure means may comprise a venturi supplied with pumping water for aspirating the diffusate. By increasing the negative pressure, it is possible to remove more solution from the dialyzer than would conventionally be accounted for by the dialysate solution supplied and the addition of impurities. While excessive negative pressure might rupture the dialyzer membrane and withdraw blood into the dialysate solution, it is possible by application of a lesser negative pressure to reduce the quantity of undesired liquids accumulated by the patient. The application of the negative pressure value may be rather critical and the quantity of fluid removed from the patient is not easily predetermined.